Update triggers in windows pipeline (#503)
Update triggers in windows pipeline (#503)

* Update triggers in windows pipeline

This makes staging the only manual step in Concourse.

* Flip logic of trigger statement

Converts 7 lines into a 1 liner
GoogleCloudPlatform/guest-test-infra,GoogleCloudPlatform/guest-test-infra,GoogleCloudPlatform/guest-test-infra